1. Technical Field
This invention relates to an elevator system and, more particularly, to an elevator system having an active roller guide (ARG).
2. Discussion of Related Art
U.S. Pat. No. 5,810,120, shows and describes an elevator control system for active roller guides having front-to-back rollers arranged on horizontal pivots, having electromagnets for vibration control and having solenoids for centering control.
FIG. 1 of the present application shows the active roller guide system shown in FIG. 2 of U.S. Pat. No. 5,810,120. The reference numerals used herein are the same as that used in U.S. patent application Ser. No. 08/741,751, and reference is made thereto as background for a more detailed description thereof.
In summary, FIG. 1 herein shows a simplified diagram of a roller guide assembly generally indicated as 40 for the purpose of discussing the basic operation of each roller guide assembly. As shown, the actuator assembly 40 includes a solenoid and magnet base 42 having a pivot support 44 mounted thereon. The actuator assembly 40 also includes a pivot bar 46 mounted on the pivot support 44 for pivoting about a pivot axis 48, and a roller arm 50 mounted on the pivot bar 46 with a roller axis 52. The actuator assembly 40 also includes a solenoid 54, a spring 56, an electromagnet 58 and a ferromagnetic plate 60. The actuator assembly 40 responds to control signals from the elevator car controller 20 that is in turn responsive to sensed elevator car signals. The control signals include a solenoid centering elevator car control signal on a line 61a to the solenoid 54 to control the centering or coarse position of an elevator car (not shown) in relation to guide rails (not shown) of an elevator hoistway (not shown), and an electromagnet vibration elevator car control signal on a line 61b to the electromagnet 58 to control the vibration and/or the fine position of the elevator car via rollers in relation to the guide rails of the elevator hoistway.
One of the disadvantages of using solenoids for centering control is that solenoids have a mechanical component to them that results in undesirable clacking and/or wearing; moreover, solenoids increase the parts count of the overall elevator design, significantly increase technical risk, require more adjustment, and generally decrease the robustness of the elevator control system.
U.S. Pat. No. 5,810,120 does not show or describe an elevator system having an active roller guide system with either front-to-back rollers arranged on horizontal pivots or the use of all electromagnets for both vibration and centering elevator car control as disclosed below. The subject matter of U.S. Pat. No. 5,810,120 is assigned to the assignee of the present application, and hereby incorporated by reference.